The main reason for the brittleness of beryllium bronze after heat treatment is related to the internal structure of the material and the heat treatment process. The following is a detailed analysis:

The influence of grain boundary oxides and inclusions

During the heat treatment process of beryllium bronze, oxides and inclusions may form at the grain boundaries within the material. These impurities will disrupt the bonding state between copper, tin, and beryllium, resulting in an uneven internal structure of the material and thereby reducing its toughness, manifested as brittleness.

Excessive cooling rate

The cooling rate after heat treatment has a significant impact on the material properties. If the cooling rate is too fast, it will cause large internal stress within the material. This stress concentration can lead to brittle fracture. Therefore, controlling an appropriate cooling rate is the key to avoiding brittleness.

Improper heat treatment

The aging heat treatment (precipitation hardening) of beryllium bronze is an important step in improving its properties. If the aging temperature or time is chosen improperly, it may result in the material having excessively high hardness but insufficient toughness, leading to brittleness. For instance, an excessively high aging temperature or a too long holding time will cause excessive second-phase precipitates to form within the material, reducing its ductility.

Uneven material composition

The composition of beryllium bronze (such as the ratios of copper, tin, and beryllium) has a direct impact on the material's performance. If the composition is uneven or the impurity content is too high, it will exacerbate the brittleness problem after heat treatment.

Inconsistent heat treatment process parameters

The heat treatment process parameters (such as heating temperature, holding time, cooling method, etc.) need to be optimized based on the specific material and application scenario. If the parameters are improperly selected, it may lead to a decline in material performance, including an increase in brittleness.

By implementing the above measures, the brittleness problem of beryllium bronze after heat treatment can be effectively reduced, and its comprehensive performance can be improved. If you need to know more about the specific process parameters, you can search for the heat treatment process of beryllium bronze or the aging treatment parameters.